Conventionally, a data processing apparatus which allows the user to easily recognize the contents of still images and the like and to easily manage files of still images and the like upon playing back still images, motion images, and audio stored in a storage medium using a memory card having a solid memory element as the storage medium is known. A digital still camera or the like can play back not only data sensed/stored by itself but also data stored by another data processing apparatus, as long as data is stored on a compatible storage medium.
Such data processing apparatus can load and play back data from a detachable non-volatile memory. Even when a non-volatile memory is built in and is not detachable, another data processing apparatus is connected to store and save data there, and the saved data can be loaded and played back.
In case of a digital still camera or the like, not only data obtained by another data processing apparatus but also image data obtained by photoelectrically converting an optical image photographed by a photographing lens by a photoelectric conversion element, and audio data obtained by A/D converting an audio signal stored via a microphone are temporarily saved in a volatile memory, and the image and audio data are transferred to and saved in a storage medium. Also, playback is made by transferring the image and audio data from the storage medium to the volatile memory.
However, such conventional data processing apparatus adopts a file system (e.g., FAT (File Allocation Table) file system or the like) that seeks and plays back a target file by seek unit that seeks used cluster information in only the forward direction. In the data processing apparatus with such file system, when a playback process is done by randomly accessing data by quick forward scan or reverse scan, a seek time required to access the target data position becomes less negligible with increasing file size, thus imposing stress on the user.